[AI-FSSDK] [FSSDK-12337] Add Feature Rollout support by FarhanAnjum-opti · Pull Request #499 · optimizely/python-sdk

FarhanAnjum-opti · 2026-03-03T19:47:39Z

Summary

Adds Feature Rollout support to the Python SDK. Feature Rollouts are a new experiment rule type that combines Targeted Delivery simplicity with A/B test measurement capabilities. During project config parsing, the "everyone else" variation from the flag's rollout is injected into any experiment with type "feature_rollout", enabling correct evaluation without changes to decision logic.

Changes

Added optional type string field to the Experiment data model
Added config parsing logic to inject the "everyone else" rollout variation into feature_rollout experiments
Added traffic allocation entry (endOfRange=10000) for the injected variation
Added _get_everyone_else_variation helper method to extract the last rollout rule's first variation
Added 16 unit tests covering feature rollout injection, edge cases, and backward compatibility

Jira Ticket

FSSDK-12337

…g parsing

- Move feature rollout tests from standalone test_feature_rollout.py into test_config.py following module-level testing convention - Use base.BaseTest instead of unittest.TestCase for consistency - Fix mypy strict type errors in Variation construction using cast - All checks pass: ruff, mypy --strict, pytest (941/941) Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

- Inline _get_everyone_else_variation logic, remove unnecessary static method - Use get_rollout_from_id() to match TDD pseudocode - Remove isinstance check (rollout experiments are always dicts) - Remove 3 unit tests for deleted helper method (edge cases already covered by integration-level tests) Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

- Restore as instance method matching TDD pseudocode structure - Takes flag (FeatureFlag) param, calls get_rollout_from_id internally - Caller simplified to: everyone_else_variation = self._get_everyone_else_variation(flag)

- Add ExperimentTypes enum in helpers/enums.py with AB, MAB, CMAB, FEATURE_ROLLOUT - Use ExperimentTypes.FEATURE_ROLLOUT constant in config parsing instead of raw string

- Add ExperimentType Literal type in helpers/types.py: 'a/b', 'mab', 'cmab', 'feature_rollout' - Change Experiment.type from Optional[str] to Optional[ExperimentType]

…check - Remove redundant ExperimentTypes class from enums.py (ExperimentType Literal suffices) - Simplify getattr(experiment, 'type', None) to experiment.type

jaeopt · 2026-03-04T16:15:34Z

+ # Feature Rollout support: inject the "everyone else" variation
+ # into any experiment with type == "feature_rollout"
+ everyone_else_variation = self._get_everyone_else_variation(feature)
+ if everyone_else_variation is not None:


We need this condition to the ticket prompt -
if everyone_else is null, we need handle specially. Let's discuss.

jaeopt · 2026-03-04T16:20:42Z

+ var_entity = entities.Variation(
+ id=everyone_else_variation['id'],
+ key=everyone_else_variation['key'],
+ featureEnabled=bool(everyone_else_variation.get('featureEnabled', False)),
+ variables=cast(
+ Optional[list[entities.Variable]],
+ everyone_else_variation.get('variables'),
+ ),
+ )


Can this be returned by _get_everyone_else_variation() instead of building redeatedly?
We can try add this to the prompt.

…lse_variation - Build Variation entity once in helper, derive dict from it in caller - Addresses PR review comment from jaeopt

Removed 7 tests that were covered by other tests: - test_experiment_type_field_parsed (covered by injection test) - test_feature_rollout_with_empty_rollout_experiments (similar to no_rollout) - test_feature_rollout_multiple_experiments_mixed_types (covered by injection + unchanged) - test_feature_rollout_flag_variations_map_includes_injected (subset of maps test) - test_experiment_type_ab (just string assignment) - test_feature_rollout_with_variables_on_everyone_else (edge case) - test_existing_datafile_not_broken (covered by none_when_missing + unchanged)

muzahidul-opti · 2026-03-09T17:12:01Z

+ if not variations:
+ return None
+
+ variation_dict = variations[0]


Is it save to access? What happen if it is empty

It is safe. Line 722-723 ensures its not empty and if empty None is returned.

jaeopt

Looks good. A couple of changes suggested.

jaeopt · 2026-03-09T18:17:50Z

 trafficAllocation: int


+ExperimentType = Literal['a/b', 'mab', 'cmab', 'feature_rollout']


flags have these types -
class RuleTypes(enum.Enum):
targeted_delivery = "targeted_delivery"
ab = "a/b"
multi_armed_bandit = "multi_armed_bandit"
contextual_multi_armed_bandit = "contextual_multi_armed_bandit"
if we want to keep short names - let's consistent. what about
{"ab", "mab", "cmab", "td", "fr"}

We can specify these types in the ticket.
Also need to update TDD as well.

…livery type - Add ExperimentTypes class in enums.py with ab, mab, cmab, td, fr - Add 'targeted_delivery' to ExperimentType Literal in types.py - Use enums.ExperimentTypes.fr constant in injection check - Add test for type field parsing from datafile

Remove test_feature_rollout_everyone_else_is_last_rollout_rule to match updated Jira ticket test requirements.

Update ExperimentTypes and ExperimentType Literal to use actual backend values: 'multi_armed_bandit' and 'contextual_multi_armed_bandit' instead of shorthand 'mab' and 'cmab'.

…abbreviations

esrakartalOpt

All comments are implemented. Looks good to me 👍

jaeopt

LGTM

[AI-FSSDK] [FSSDK-12337] Add Feature Rollout support to project confi…
159ee1b
…g parsing

optimizely-codereview-bot assigned FarhanAnjum-opti Mar 3, 2026

FarhanAnjum-optiand others added 6 commits March 4, 2026 02:07

[AI-FSSDK] [FSSDK-12337] Add ExperimentTypes constants for type field
397bacd
- Add ExperimentTypes enum in helpers/enums.py with AB, MAB, CMAB, FEATURE_ROLLOUT - Use ExperimentTypes.FEATURE_ROLLOUT constant in config parsing instead of raw string

[AI-FSSDK] [FSSDK-12337] Type-restrict Experiment.type to ExperimentType
d95f1e8
- Add ExperimentType Literal type in helpers/types.py: 'a/b', 'mab', 'cmab', 'feature_rollout' - Change Experiment.type from Optional[str] to Optional[ExperimentType]

[AI-FSSDK] [FSSDK-12337] Remove ExperimentTypes class, simplify type …
3f05ad8
…check - Remove redundant ExperimentTypes class from enums.py (ExperimentType Literal suffices) - Simplify getattr(experiment, 'type', None) to experiment.type

jaeopt reviewed Mar 4, 2026
View reviewed changes

FarhanAnjum-opti added 2 commits March 4, 2026 23:35

[AI-FSSDK] [FSSDK-12337] Return Variation entity from _get_everyone_e…
c73f410
…lse_variation - Build Variation entity once in helper, derive dict from it in caller - Addresses PR review comment from jaeopt

FarhanAnjum-opti changed the title ~~[AI-FSSDK] (DO NOT REVIEW) [FSSDK-12337] Add Feature Rollout support~~[AI-FSSDK] [FSSDK-12337] Add Feature Rollout supportMar 5, 2026

muzahidul-opti reviewed Mar 9, 2026
View reviewed changes

jaeopt requested changes Mar 10, 2026
View reviewed changes

FarhanAnjum-opti added 6 commits March 10, 2026 23:24

[AI-FSSDK] [FSSDK-12337] Remove test not in ticket spec
14d288d
Remove test_feature_rollout_everyone_else_is_last_rollout_rule to match updated Jira ticket test requirements.

[FSSDK-12337] Fix experiment type values to match backend
3da60b5
Update ExperimentTypes and ExperimentType Literal to use actual backend values: 'multi_armed_bandit' and 'contextual_multi_armed_bandit' instead of shorthand 'mab' and 'cmab'.

Format ExperimentType definition for ruff check
3a52b56

[AI-FSSDK] [FSSDK-12337] Update experiment type values to short-form …
0c56c4d
…abbreviations

[AI-FSSDK] [FSSDK-12337] Add validation for experiment type field
39f9cec

FarhanAnjum-opti requested a review from jaeopt March 17, 2026 02:56

trigger CI
04ea47f

esrakartalOpt approved these changes Mar 30, 2026
View reviewed changes

jaeopt approved these changes Mar 30, 2026
View reviewed changes

FarhanAnjum-opti merged commit 55924e5 into masterMar 30, 2026
15 checks passed

FarhanAnjum-opti deleted the ai/farhananjum-opti/FSSDK-12337-feature-rollouts branch March 30, 2026 19:57

FarhanAnjum-opti mentioned this pull request Apr 28, 2026
[FSSDK-12521] chore: preparing for release v5.5.0 #508
Merged

Navigation Menu

Uh oh!

[AI-FSSDK] [FSSDK-12337] Add Feature Rollout support - #499

[AI-FSSDK] [FSSDK-12337] Add Feature Rollout support#499
FarhanAnjum-opti merged 16 commits into
masterfrom
ai/farhananjum-opti/FSSDK-12337-feature-rollouts

FarhanAnjum-opti commented Mar 3, 2026•
edited by atlassian Bot
Loading

Uh oh!

jaeoptMar 4, 2026

Uh oh!

jaeoptMar 4, 2026

Uh oh!

muzahidul-optiMar 9, 2026

Uh oh!

FarhanAnjum-optiMar 10, 2026•
edited
Loading

Uh oh!

jaeopt left a comment

Uh oh!

jaeoptMar 9, 2026

Uh oh!

jaeoptMar 9, 2026

Uh oh!

Uh oh!

esrakartalOpt left a comment

Uh oh!

jaeopt left a comment

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

		trafficAllocation: int


		ExperimentType = Literal['a/b', 'mab', 'cmab', 'feature_rollout']

Uh oh!

Conversation

FarhanAnjum-opti commented Mar 3, 2026• edited by atlassian BotLoading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Summary

Changes

Jira Ticket

Uh oh!

jaeoptMar 4, 2026

Choose a reason for hiding this comment

Uh oh!

jaeoptMar 4, 2026

Choose a reason for hiding this comment

Uh oh!

muzahidul-optiMar 9, 2026

Choose a reason for hiding this comment

Uh oh!

FarhanAnjum-optiMar 10, 2026• edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

jaeopt left a comment

Choose a reason for hiding this comment

Uh oh!

jaeoptMar 9, 2026

Choose a reason for hiding this comment

Uh oh!

jaeoptMar 9, 2026

Choose a reason for hiding this comment

Uh oh!

Uh oh!

esrakartalOpt left a comment

Choose a reason for hiding this comment

Uh oh!

jaeopt left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

FarhanAnjum-opti commented Mar 3, 2026•
edited by atlassian Bot
Loading

FarhanAnjum-optiMar 10, 2026•
edited
Loading